(1) Field of the Invention
The invention relates to a rolling device for a sliding leaf of a door, window or the like, including a slide in the shape of a casing having, at the level of its side walls, several recesses of a progressively larger height with respect to the lower edge of these side walls, these recesses receiving spindle ends of at least two railwheels locked at the top by narrowings. The casing is secured, through adequate fixing means, in a groove and/or a slot present in the lower edge of the sliding leaf.
(2) Description of the Prior Art
Many rolling devices meeting the above description are already known.
Thus, such rolling devices for sliding leaves include a slide in the shape of a substantially parallelepipedically shaped casing. This casing is defined by two side walls parallel to each other, an upper wall and transversal walls closing same at each of its front and rear ends. At the bottom of this casing partly protrude railwheels corresponding to the rolling means and rotatingly mounted about horizontal spindles.
Usually, this slide is rigidly mounted in the groove or in the slot provided for this purpose in the lower edge of the profile bar corresponding to the lower rail of the sliding leaf. Now, the fact of thus being rigidly maintained in this groove or in this slot does, in the event of a lack of parallelism between the lower rail of the leaf and the guiding rail on which rests this leaf, not allow both railwheels of the rolling device to simultaneously co-operate with this guiding rail. As a result, the single railwheel in contact will be heavily strained during the movement of the sliding leaf. It will therefore tend to get prematurily worn, so that one will have to periodically replace the railwheel in order to maintain the desired orientation of the leaf. In this respect, the usual approach is to form the stiles in parallel relationship on the leaf and the sash-frame, rather than their respective rails.
Therefore, solutions have been conceived for individually adjusting the position of the railwheels.
U.S. Pat. No. 3,208,109 provides a rolling device in which the user may individually act on each of the railwheels to adjust their protruding position with respect to the bottom of the casing, with a view to adjusting the position of the leaf with respect to the sash-frame. Thus, the tangent to the railwheels may be more or less inclined with respect to the axis of the lower rail of the sliding leaf. However, since in this case adjusting can be carried out only stepwise, it is sure that in 98% of the cases, one will fall back into the above-mentioned configuration, that is to say, the ideal adjustment of the leaf with respect to the sash-frame win correspond to the situation in which only one railwheel effectively rests on the guiding rail present at the level of the lower rail of said sash-frame.
Finally, it would be necessary to be able to more accurately adjust this height position of each of the railwheels, in order to cope with the problem set forth.